JPH10278202A - Multilayered stretched polyamide film and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered stretched polyamide film having excellent transparency, tensil strength, ply separation strength, gas barrier properties and dimensional stability, excellent in retort resistance and suitable for packing at economical cost. SOLUTION: This film consists of at least three layers, that is, a resin layer (X) formed from a compsn. prepared by adding 0.5-3 wt.% of the following polymeric compd. P to polyamide (A) formed from a xylylenediamine component and a 4-12C aliphatic dicarboxylic acid component, a resin layer Y of aliphatic polyamide (B) and the polyamide layer Z containing 50-80 wt.% of polyamide (A) and 50-20 wt.% of polyamide (B) provided between both layers (X), (Y). The polymeric compd. P is modified polyethylene consisting of 95-50 wt.% of ethylene, 0.1-10 wt.% of unsaturated dicarboxylic acid and or its deriv. and 4.9-40 wt.% of unsaturated carboxylic acid and/or its lower alkyl ester deriv.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention has excellent transparency, tensile strength, delamination strength, pinhole resistance, gas barrier properties, dimensional stability, and excellent retort resistance (hot water treatment resistance). The present invention relates to a multilayer stretched polyamide film suitable for packaging and a method for producing the same.

[0002]

2. Description of the Related Art Various plastic film packaging bags are used in large quantities for packaging foods, medicines, miscellaneous goods, etc. Usually, a biaxially stretched plastic film is used as a base film and a heat sealable sealant film ( For example, a laminated film obtained by laminating a non-oriented film) is used. The base film is required to have excellent properties such as transparency, pinhole resistance, gas barrier properties, dimensional stability, and tensile strength, and also has excellent delamination strength with a sealant film. It is necessary. However, recent demands for long-term preservation of the contents of the package require the quality of the packaging materials to be improved, and in order to provide advanced gas barrier properties, the surface of the biaxially stretched polyamide film is coated with a vinylidene chloride-based polymer latex. Such films are widely used, but have the disadvantage that they become cloudy due to hot water treatment.

[0003] Further, a film using polymethaxylylene adipamide (hereinafter referred to as MXD6) synthesized from adipic acid and metaxylylenediamine as a raw material has excellent gas barrier properties, but has poor pinhole resistance. For this reason, multilayer films have been proposed which are mixed with another polyamide resin, coextruded with a resin layer of polyamide, polyester, polyolefin or the like, or laminated.

For example, a biaxially stretched film formed from a mixture of MXD6 and an aliphatic polyamide (Japanese Patent Laid-Open No.
No. 4176), a biaxially stretched film obtained by laminating MXD6 and an aliphatic polyamide by a tubular method (JP-A-57-51427).
JP-A-56-155762, a three-layer film having a surface layer composed of a mixture of MXD6 and an aliphatic polyamide and an intermediate layer mainly composed of MXD6 (JP-A-56-155762), wherein at least one layer is composed of MXD6 and / or an aliphatic polyamide. Film consisting of a mixture of a polyamide and an amorphous polyamide
No. -59244).

However, in a biaxially stretched film using a mixture of MXD6 and an aliphatic polyamide as a raw material, it is difficult to provide both gas barrier properties and pinhole resistance, and the aliphatic polyamide and MXD6 are laminated. In this case, there was a disadvantage that the layers were easily delaminated. Also,
Even in the case of the configuration disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 56-155762, the pinhole resistance was insufficient, and there was a problem of delamination. According to the method disclosed in Japanese Patent Application Laid-Open No. 4-59244, the problem of delamination is improved, but performance such as pinhole resistance is insufficient when applied to a wide range of applications. .

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks and has excellent transparency, tensile strength, delamination strength, gas barrier properties, dimensional stability, and excellent retort resistance. The purpose of the present invention is to provide a multilayer stretched polyamide film suitable for packaging applications at an economical price. That is, specifically, the aliphatic polyamide resin layer and the MX
There is no delamination phenomenon between the D6 resin layers, and in addition to the excellent mechanical properties, pinhole resistance and transparency of the aliphatic polyamide resin layer, the heat resistance and gas barrier properties of the MXD6 resin layer are combined. It is an object of the present invention to provide a multilayer stretched polyamide film suitable as a packaging material and a method for producing the same.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a multilayer stretched film in which a composition comprising a specific component is laminated can solve these problems. Reached the present invention.

That is, the gist of the present invention is as follows. (1) Polyamide (A) formed from a xylylenediamine component and an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms
And a resin layer (X) containing 0.5 to 3% by weight of the following polymer compound P and a resin layer (Y) of an aliphatic polyamide (B), and a polyamide (A) of 50 to 80% by weight. A multilayer stretched polyamide film comprising at least three layers, having a polyamide resin layer (Z) containing 50 to 20% by weight of a polyamide (B). Polymer compound P: 95 to 50% by weight of ethylene, 0.1 to 10% by weight of unsaturated dicarboxylic acid and / or derivative thereof, unsaturated carboxylic acid and / or lower alkyl ester derivative thereof
Modified polyethylene comprising 4.9 to 40% by weight. (2) Polyamide (A) formed from a xylylenediamine component and an aliphatic dicarboxylic acid component having 4 to 12 carbon atoms
In the middle of the resin layer (X) containing 0.5 to 3% by weight of the polymer compound P and the resin layer (Y) of the aliphatic polyamide (B), 50 to 80% by weight of the polyamide (A) and the polyamide ( B) A method for producing a multilayer stretched polyamide film comprising at least three layers, having a polyamide resin layer (Z) containing 50 to 20% by weight, the resin layer (Z)
A method for producing a multilayer stretched polyamide film, characterized in that a polyamide (A) and a polyamide (B) are co-extruded using a resin in which the polyamide (A) and the polyamide (B) are melt-kneaded in advance.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The polyamide (A) in the present invention comprises
Or, it is a polyamide obtained by a polycondensation reaction from paraxylylenediamine and an aliphatic dicarboxylic acid having 4 to 12 carbon atoms, and in particular, MXD6 synthesized from metaxylylene and adipic acid is preferable.

In the present invention, the aliphatic polyamide (B)
Examples thereof include nylon 6, nylon 66, nylon 46, nylon 610, nylon 612, nylon 12, nylon 11, copolymerized polyamides thereof, and mixed polyamide resins, and nylon 6 is particularly preferred.

The polyamides (A) and (B) generally do not have good adhesiveness, and the resin layer (Z) composed of a molten mixture of the polyamides (A) and (B) is laminated as an intermediate layer to form the polyamide (A). And (B) are improved in delamination strength of the resin layer. Further, as the resin layer (Z), multi-layer coextrusion using a resin in which polyamide (A) and (B) are melt-mixed in advance, the delamination strength of each resin layer is further improved. As a condition for mixing the polyamides (A) and (B), it is preferable to extrude the mixture in a temperature range of 250 to 300 ° C. using a twin-screw extruder. If the temperature is below 250 ° C,
The effect of improving delamination strength is insufficient,
When the temperature exceeds 300 ° C., the resin does not bite into the extruder.

The resin layer (Z) is made of polyamide (A) 50-80.
It is necessary to have a mixing ratio of 50% by weight to 50% by weight of the polyamide (B). If the mixing ratio is out of the above range, the delamination strength is not sufficient.

In the present invention, the polymer compound P is composed of 95 to 50% by weight of ethylene, 0.1 to 10% by weight of an unsaturated dicarboxylic acid having 3 to 8 carbon atoms and / or a derivative thereof, and 0.1 to 10% by weight of an unsaturated carboxylic acid and / or an unsaturated carboxylic acid. The lower alkyl ester derivative is an ethylene terpolymer composed of 4.9 to 40% by weight, and has a melt index of 0.1 to 60 g / 10 minutes, preferably 1 to 50 g / 10 minutes.

The unsaturated dicarboxylic acids and derivatives thereof include, for example, maleic acid, fumaric acid, itaconic acid,
Derivatives such as citraconic acid, mesaconic acid and their metal salts and acid anhydrides are included. Among these, maleic anhydride is most preferred from the viewpoint of cost performance and the like.

Examples of the unsaturated carboxylic acid and its lower alkyl ester derivative include acrylic acid, methacrylic acid, etc., methyl acrylate, methyl methacrylate, ethyl acrylate, n-propyl acrylate, and the like.
Isopropyl acrylate, n-butyl acrylate,
Examples thereof include isobutyl acrylate and t-butyl acrylate, and n-butyl acrylate is particularly preferable.

The amount of the polymer compound P in the resin layer (X) is 0.5 to 3% by weight, preferably 1 to 2% by weight.
If it is less than 0.5% by weight, the effect of improving pinhole resistance is insufficient, and if it exceeds 3% by weight, the oxygen permeability tends to decrease, which is not preferable.

Further, talc is added to the resin layer (X) in an amount of 0.01 to 0.01%.
By adding 0.5% by weight, preferably 0.05 to 0.3% by weight, the strength of the obtained multilayer stretched polyamide film can be improved. The amount of talc to be mixed is 0.01
If less than 0.5% by weight, the effect of improving strength is not exhibited, and 0.5% by weight
If the amount exceeds the above range, not only the effect of improving the strength is saturated but also the haze of the film is impaired, which is not preferable.

The structure of the multilayer stretched polyamide film in the present invention needs to have at least three layers consisting of X / Z / Y, but the structure of the layers may be appropriately changed according to the application and purpose.

As a typical layer structure, for example, a product having a five-layer structure such as Y / Z / X / Z / Y has physical properties in terms of transparency, tensile strength, gas barrier property and the like of the obtained multilayer film. It is particularly suitable for balance.

The multilayer stretched polyamide film of the present invention comprises:
Tensile strength 23 to 35 kg / mm ² , pinhole generation number 3 or less,
It preferably has properties such as a hot water shrinkage of 0.5 to 3.5%, a haze of 6% or less, an oxygen permeability of 6 cc / atm / m ² / day or less, and a delamination strength of 350 g / 15 mm or more. The tensile strength and the hot water shrinkage are both average values in the machine direction (MD) of the film and in the direction perpendicular to the film (TD).

If the tensile strength is less than 23 kg / mm ^{2, the} strength of the packaging bag will be insufficient, and if it exceeds 35 kg / mm ² , not only will the quality be excessive, but rather the workability during film production will be impaired. Not economically favorable. If the number of pinholes exceeds three, the strength of the packaging bag becomes insufficient, which is not preferable. If the hot water shrinkage rate exceeds 3.5%, problems such as curling in the process of manufacturing the packaging bag will occur. Absent.

If the haze exceeds 6%, the commercial value of the packaging bag is reduced, which is not preferable, and the oxygen permeability is 6 cc / a.
If it is greater than tm / m ² / day, the protection of the contents as a packaging bag will be insufficient. Further, the delamination strength is desirably larger than 350 g / 15 mm in practical performance when it is used as a packaging bag. The tensile elongation may be usually in the range of 80 to 130% (average value of MD and TD).

As the method for producing the multilayer polyamide film in the present invention, any known method can be employed. That is, a method in which each resin constituting each layer is melted using a separate extruder, extruded from a die after being superimposed by a feed block method, and several types of molten resins are extruded after being superimposed in a multi-manifold die. A method, a method of bonding each resin layer by lamination, a method of combining these, and the like can be used.

Further, as a stretching method of the multilayer film,
Flat type sequential biaxial stretching method, flat type simultaneous biaxial stretching method, tubular method and the like can be used,
The flat simultaneous biaxial stretching method is most preferable in order to obtain the uniformity of the thickness of the multilayer film and the uniformity of the physical properties in the vertical and horizontal directions.

Next, a production method by the flat simultaneous biaxial stretching method will be described. For example, first, using a three-type, five-layer co-extrusion T-die, a nylon 6 is extruded from an extruder (a), and a composition comprising MXD6, modified polyethylene (P) and, if necessary, talc is extruded from an extruder (b). The composition consisting of nylon 6 and MXD6 was supplied to each of 230 to 280 from the machine (c).
The multilayer unstretched sheet is extruded in a temperature range of ° C., and is rapidly cooled by being closely adhered to a cooling drum whose temperature is adjusted to room temperature or lower.

In producing an unstretched multilayer polyamide sheet, as a method for rapidly cooling the resin extruded from the die on a cooling drum, an electrostatic application casting method is not preferable. , The molten resin is pressed against a rotating cooling roll to cool the resin. The reason is that in the multilayer polyamide sheet of the present invention,
Since the electrostatic properties of the resin layer (X) and the resin layer (Y) are different, when the electrostatic application casting method is used, unevenness in film formation occurs, operability is reduced, and film formation becomes difficult. Because there is.

Next, the obtained sheet is passed through a hot water bath whose temperature is controlled at 40 to 70 ° C., the water content is adjusted to 3 to 7%, and the sheet is preheated to 140 to 210 ° C. After simultaneously biaxially stretching at a stretching ratio of 2 to 4 times at 220 ° C. at a stretching ratio of 2 to 4 times, relaxing at 1 to 5% in the transverse direction, and then performing a heat treatment at 150 to 220 ° C. for several seconds to obtain a multilayer stretched film having a desired thickness. Can be obtained.

If the temperature of the hot water bath is lower than 40 ° C., the impregnating time required for making the unstretched multilayer sheet to have a constant moisture content becomes long, which is not economical. If the temperature is higher than 70 ° C., the sheet is deformed during impregnation. I do. Also, even if the moisture content is lower than 3%, 7%
If it is higher, the stretchability decreases. When the preheating temperature and the stretching temperature are out of the above ranges, stretching unevenness occurs,
It is not preferable because the film breaks during stretching.

The larger the stretching ratio, the higher the strength of the film. However, from the viewpoint of stretching stability, it is preferably about 2 to 4 times in each of length and width. The stretching ratio in the longitudinal and transverse directions is preferably equal in consideration of the balance in the longitudinal and transverse directions such as tensile strength.However, in consideration of the shrinkage of the film in the transverse direction due to the relaxation treatment in the heat treatment step, the stretching ratio in the transverse direction is set to It is preferably about 1.0 to 1.2 times the direction.

By setting the production conditions within the above range, a multilayer stretched film having a difference in tensile strength and hot water shrinkage in the longitudinal and transverse directions of 10% or less and 70% or less, respectively, can be obtained. The difference between the tensile strength and the hot water shrinkage in the vertical and horizontal directions is the value obtained by dividing the absolute value of the difference between the physical properties in the vertical and horizontal directions by the average of the physical properties in the vertical and horizontal directions. Say. If the difference in tensile strength and hot water shrinkage between the vertical and horizontal directions exceeds 10% and 70%, respectively, the bag may be deformed or broken when pressure or impact is applied to the package. Occurs.

When the multilayer stretched film of the present invention is used for a packaging bag, it is usually provided with a heat seal property, and in order to further enhance gas barrier properties and mechanical strength depending on the application, polypropylene, polyethylene, or the like. It is used by laminating with a plastic film such as an ethylene-vinyl acetate copolymer or polyester, paper, or a metal foil such as aluminum.

The thickness of the multilayer stretched film in the present invention is not particularly limited, but when it is used as a flexible packaging material, a film having a thickness of 300 μm or less, usually 5 to 50 μm is used.

In order to improve the productivity of the film, an inorganic lubricant such as silica, alumina, kaolin and calcium carbonate and an organic lubricant such as ethylenebisstearylamide are usually added to improve the slip property of the film surface.

[0034]

Next, the present invention will be described more specifically with reference to examples. In addition, the raw materials used for the evaluation of the examples and comparative examples and the measuring methods are as follows.

1. Raw materials (1) Nylon 6 (N6); A1030BRF manufactured by Unitika Ltd. (2) MXD6; MX nylon 6007 manufactured by Mitsubishi Gas Chemical Company
(Relative viscosity 2.64) (3) Modified polyethylene (PE); Lexpearl ET 183B manufactured by Japan Polyolefin Co. Terpolymer of ethylene, n-butyl acrylate, maleic anhydride (4) Talc (TL); Hayashi Kaseisha UPNHS-T0.5

2. Measurement method (1) Tensile strength, elongation Measured according to ASTM-D882 using a sample having a width of 10 mm and a length of 10 cm. (2) Hot water shrinkage A sample having a width of 10 mm and a length of 10 cm was immersed in boiling water for 30 minutes, the dimensional change before and after the treatment was measured, and the percentage relative to the original length was obtained. (3) Haze Measurement was performed using a fully automatic haze meter (TC-H3DPK) manufactured by Tokyo Denshoku Co., Ltd. in accordance with JIS K-6714. Haze (%) = [Td (diffuse transmittance%) / Tt (total light transmittance%)] × 100 (4) Pinhole resistance MIL-B ・ Fed.Test Method Std.
According to Method 2017, a 12 inch x 8 inch sample is made into a cylindrical shape with a diameter of 3.5 inches, and both ends are gripped, the initial grip interval is 7 inches, and the grip interval at the maximum bending is 1 inch.
The number of pinholes generated after bending 1,000 times at 5 ° C. with a so-called gel botester (manufactured by Rigaku Corporation) at a speed of 40 times / min was counted. (5) Oxygen permeability Using OX-TRAN10-50A manufactured by Modern Control, at 20 ° C,
It was measured under the condition of 65% RH. (Unit: cc / mm ² / atm / day) (6) Delamination strength After peeling off the edge of the multilayer film with a width of 15 mm at the interface, the temperature is 20 ℃,
The peeling strength was measured by a T-peel method at a peeling speed of 300 mm / min in a 65% RH atmosphere using an autograph manufactured by Shimadzu Corporation. (7) Moisture content About 20 g of the unstretched multilayer sheet impregnated in a hot water bath is collected in a weighing bottle and precisely weighed. Next, after drying in a constant-temperature dryer at 120 ± 2 ° C. for 2 hours, the weight after gradually cooling to room temperature in a calcium chloride desiccator was precisely weighed, and the weight loss rate (%) was determined. (8) Hot water treatment resistance Unstretched polypropylene (Toray's Tolephane ZK-93K, 60 μm
), Heat seal in three directions and lengthen 14c
A rectangular filling bag measuring mx 12 cm wide was manufactured. Next, the bag was filled with 50 ml of water, and the remaining one was heat-sealed.
The appearance of the bag after the hot water treatment at 0 ° C. for 30 minutes was visually observed, and evaluated on a scale of A to C according to the following criteria. A: good B: only a small part (5% or less of the surface area of the filling bag) has poor appearance. C: Appearance failure is observed partially (5% or more of the surface area of the filling bag) or over the entire surface.

Example 1 Using a twin screw extruder PCM45 manufactured by Ikegai Co., Ltd., a mixture of 30 parts by weight of N6 and 70 parts by weight of MXD6 was mixed at an extrusion temperature of 3 parts.
After melt extrusion at 00 ° C., pelletization was performed, and the obtained pellet was dried at 140 ° C. for about 2 hours to crystallize. Using a three-type, five-layer coextrusion T-die, N6 was heated at a temperature of 250 from the extruder (a).
At a temperature of 265 ° C. (Y layer), and a mixture of 1.3% by weight of PE and 0.2% by weight of talc mixed with MXD6 from an extruder (b).
(X layer), and melt-extruded pellets of the above N6 and MXD6 from an extruder (c) at a temperature of 280 ° C. (Z layer), respectively, and extruded, and laminated in the order of Y / Z / X / Z / Y. Was extruded from a die, and was brought into close contact with a cooling drum controlled to a surface temperature of 18 ° C. and rapidly cooled, and the thickness of each layer was Y / Z /
X / Z / Y = 45/5/50/5/45 (μm) with a total thickness of 150
A μm unstretched multilayer sheet was obtained. The obtained sheet is heated to 60 ° C.
Sent to a heated water bath, and treated for 1.5 minutes
The moisture content was adjusted to 4.7%. The end of this sheet was gripped by a clip of a tenter type simultaneous biaxial stretching machine, preheated at 175 ° C, stretched at 190 ° C, stretched 3.0 times vertically and 3.3 times horizontally.
After the simultaneous biaxial stretching, the film was subjected to a heat treatment at 210 ° C. for 4 seconds at a transverse relaxation rate of 5%, and the film was cooled and wound up. /
A 15 μm thick multilayer stretched film having a Z / Y of 4.5 / 0.5 / 5.0 / 0.5 / 4.5 (μm) was obtained. Next, the obtained raw roll was slit, and the results of evaluating various film properties are shown in Table 1. As shown in Table 1, the delamination strength was good and the film had good suitability as a packaging film.

Example 2 A multilayer stretched film was produced in the same manner as in Example 1 except that the mixing ratio of MXD6 and PE for forming the X layer was set to the conditions shown in Table 1, and the performance was measured. The results are shown in Table 1.

Examples 3 and 4 A multilayer stretched film was produced in the same manner as in Example 1 except that the mixing ratio of N6 and MXD6 forming the Z layer was set to the conditions shown in Table 1, and the performance was measured. The results are shown in Table 1.

Example 5 A multilayer stretched film was produced in the same manner as in Example 1 except that the mixture of N6 and MXD6 forming the Z layer was not melt-kneaded in advance, and the performance was measured. The results are shown in Table 1.

Comparative Examples 1 to 3 The same procedures as in Example 1 were carried out except that the mixing ratio of the mixture of N6 and MXD6 forming the Z layer and the amount of PE in the X layer were as shown in Table 1. The multilayer stretched film was manufactured, and the performance was measured. The results are shown in Table 1.

COMPARATIVE EXAMPLE 4 Using a two-type three-layer co-extrusion T-die, an extruder (a)
At a temperature of 250 ° C (Y layer), and a mixture of 1.3% by weight of PE and 0.2% by weight of talc mixed with MXD6 from an extruder (b) at a temperature of 265 ° C (X layer).
The sheets laminated in the order of X / Y are extruded from a die, closely adhered to a cooling drum controlled to a surface temperature of 18 ° C., and quenched. An unstretched multilayer sheet having a total thickness of 150 μm was obtained. The obtained sheet was stretched in the same manner as in Example 1, and Y / X / Y = 5.0 /
A multi-layer stretched film of 5.0 / 5.0 (μm) having a thickness of 15 μm was obtained. Table 1 shows the measurement results in the same manner as in Example 1.

[0043]

[Table 1]

[0044]

The multilayer stretched polyamide film of the present invention has excellent transparency, tensile strength, delamination strength, gas barrier properties, and dimensional stability. And its industrial utility value is extremely high.

Claims (4)

[Claims] 1. A xylylenediamine component having 4 to 4 carbon atoms.
A resin layer (X) containing 0.5 to 3% by weight of the following polymer compound P in a polyamide (A) formed from 12 aliphatic dicarboxylic acid components, and a resin layer of an aliphatic polyamide (B) ( A multilayer stretched polyamide film comprising at least three layers, comprising a polyamide resin layer (Z) containing 50 to 80% by weight of polyamide (A) and 50 to 20% by weight of polyamide (B) in the middle of Y). Polymer compound P: 95 to 50% by weight of ethylene, 0.1 to 10% by weight of unsaturated dicarboxylic acid and / or derivative thereof, unsaturated carboxylic acid and / or lower alkyl ester derivative thereof
Modified polyethylene comprising 4.9 to 40% by weight. 2. The multilayer stretched polyamide film according to claim 1, wherein the resin layer (X) contains 0.01 to 0.5% by weight of talc. 3. The method according to claim 1, wherein the multilayer stretched film is Y / Z / X / Z /
3. The multilayer stretched polyamide film according to claim 1, comprising five layers of Y. 4. A xylylenediamine component having 4 to 4 carbon atoms.
A resin layer (X) containing 0.5 to 3% by weight of the following polymer compound P in a polyamide (A) formed from 12 aliphatic dicarboxylic acid components, and a resin layer of an aliphatic polyamide (B) ( In the middle of Y), a multilayer stretched polyamide film consisting of at least three layers, having a polyamide resin layer (Z) containing 50 to 80% by weight of polyamide (A) and 50 to 20% by weight of polyamide (B) is produced. In the method, polyamide (A) is used as the polyamide for forming the resin layer (Z).
A method for producing a multilayer stretched polyamide film, comprising coextruding a resin and a polyamide (B), which are previously melt-kneaded. Polymer compound P: 95 to 50% by weight of ethylene, 0.1 to 10% by weight of unsaturated dicarboxylic acid and / or derivative thereof, unsaturated carboxylic acid and / or lower alkyl ester derivative thereof
Modified polyethylene comprising 4.9 to 40% by weight.